|Abstract: ||本論文主要探討飼料中脂質與L-肉鹼對0.1克重點帶石斑(Epinephelus coioides)及龍膽石斑(Epinephelus lanceolatus)仔稚魚時期成長參數、存活率及體組成的影響。 實驗一:本實驗配製0、5、10、15及20%等不同脂質含量的飼料，經餵食實驗以探討點帶石斑及龍膽石斑仔稚魚脂質需求量及對成長參數；活存率及體脂肪酸組成的影響。實驗結果顯示增重率、肝體比及活存率隨著飼料脂質的添加而上升。當點帶石斑及龍膽石斑仔稚魚餵食不含油脂飼料的處理組，其肌肉中n-3高度不飽和脂肪酸(C20:5，C22:5，C22:6)組成顯著低於其他有添加油脂的處理組，隨著飼料中油脂的添加量增加，其肌肉中的Eicosapentaenoic acid (EPA, C20:5 n-3)及Docosahexaenoic acid (DHA, C22:6 n-3)含量隨之上升。使用增重率與飼料實際脂質含量以斷線迴歸分析得點帶石斑仔稚魚飼料最適脂質含量為95g/kg diet；龍膽石斑仔稚魚飼料最適脂質含量為140g/kg diet。 實驗二:本實驗以魚油，亞麻油，芝麻油，大豆油，橄欖油及牛油等不同脂質來源配製的飼料，探討飼料不同脂肪酸組成對於點帶石斑及龍膽石斑仔稚魚成長參數、活存率及體脂肪酸組成的影響。實驗結果顯示魚油含有豐富的必須脂肪酸，而其他油脂來源則缺乏n-3高度不飽和脂肪酸，因此飼料中n-3高度不飽和脂肪酸可促進石斑魚仔稚魚變態期中魚體成長並維持正常的生理功能。石斑魚為維持正常成長發育重點在於可提供組織發育過程中所必須的高度不飽和脂肪酸，除此之外，脂質亦可提供較高的能量以供應成長所需。 實驗三:本實驗以不同含量脂質(5%及14%)及L-carnitine(0%，0.5%及1%)設計2×3複因子實驗以探討對龍膽石斑仔稚魚時期成長、活存率及體組成與脂肪酸組成的影響。結果顯示餵食14%脂質添加0.5%L-carnitine有助於石斑魚苗的成長，肝臟及肌肉組織中脂質的含量也會隨著飼料中脂質含量增加而增加，隨L-carnitine添加則顯著降低肝臟及肌肉組織中脂質含量，肌肉蛋白質含量則隨L-carnitine的添加而顯著上升。肝臟及肌肉組織中脂肪酸組成顯著受L-carnitine和脂質相互作用所影響，其中又以n-3高度不飽和脂肪酸含量隨脂質添加量增加而上升，隨 L-carnitine添加而下降。 實驗四:實驗以脂質(5%及14%)、L-carnitine (0%及0.5%)及L-lysine (0%及2.83%)設計一2×2×2複因子實驗以探討龍膽石斑仔稚魚成長、活存率及體組織脂肪酸組成之影響。實驗結果顯示脂質及L-carnitine有助於石斑魚仔稚魚的成長，而且也顯著影響肝體比及組織脂肪酸的組成等參數，但L-lysine則無助於仔稚魚的發育成長。L-carnitine與脂質顯著影響肌肉蛋白質與肌肉及肝臟脂質含量。L-lysine顯著降低肌肉脂質含量，以及顯著增加肌肉蛋白質。飼料中脂質與L-carnitine的添加顯著影響肌肉及肝臟中n-3高度不飽和脂肪酸含量，其含量隨著脂質添加量增加而上升，隨L-carnitine加量增加而下降。L-lysine對於組織中n-3 HUFA含量的影響會因餵飼飼料脂質的添加量不同而有顯著的影響。5%脂質及14%脂質處理組中，L-carnitine顯著影響肌肉DHA組成含量，而L-lysine則在14%脂質處理組中顯著降低肌肉DHA組成含量。肝臟中DHA含量隨著飼料中L-carnitine及L-lysine的添加量增加而降低。肝臟中EPA含量隨著飼料中L-carnitine的添加而下降，但不受L-lysine的添加量的影響。 本論文結果顯示， 0.1克重石斑魚仔稚魚可以以人工飼料取代餌料生物，如輪蟲及豐年蝦，微粒飼料含一定含量的脂質及脂肪酸，可以提供在仔稚魚成長過程中組織及神經的發育所需。L-carnitine的添加有助於石斑魚仔稚魚脂肪酸β-氧化力的提升，因此有效的將蛋白質使用在成長上，進而達到蛋白質節約效果。石斑魚仔稚魚利用L-lysine自行轉換成L-carnitine的能力還無法確立。L-lysine轉換成L-carnitine的過程中需要六種元素(Lysine, Methionine, Niacin, Vitamin B6, Vitamin C and Iron)及五種酵素(acyl-CoA, acyl-carnitine, CATⅠ, CATⅡ, CoA)。在本實驗的魚苗正處仔稚魚期，其生長發育還不完整，如在轉換過程中缺乏某一項因素，則L-lysine轉換成L-carnitine的途徑即不完整，因此未來可繼續探討仔稚魚發育期間相關能量代謝酵素的發展。|
This study was discriminate two major subject experiments were conducted to grouper larvae (Epinephelus coioides and Epinephelus lanceolatus). The first part experiment was carried out to investigate effects of dietary lipid level and source on the growth, survival and body tissue fatty acid profiled for grouper larvae (E. coioides and E. lanceolatus). Second part experiment was carried out to investigate effects of different lipid, L-carnitine and L-lysine levels on the growth, survival and body tissue fatty acid profiled for grouper larvae (E. lanceolatus). Experiment1：Two experiments were conducted to determine the effects of dietary lipid levels on the growth, muscle fatty acid profile and survival grouper larvae E. coioides and E. lanceolatus during metamorphosis. The optimum dietary lipid requirement of E. coioides was 95 g lipid /kg diet. For E. lanceolatus, the optimum dietary lipid requirement was 75 g lipid /kg diet. The results showed that dietary lipid significantly influenced the survival and growth of grouper larvae. In experiment diet without lipid supplementation, fatty acid levels were lower than diet with lipid supplementation. Especially n-3 highly unsaturated fatty acids (n-3 HUFA) level in diet without lipid was 5.47% and that was increased when dietary lipid increased. In muscle, fatty acid compositions of grouper larvae were directly reflected by dietary fatty acid composition. Fish fed the diet without lipid showed the lowest n-3 HUFA (C20:5, C22:5, C22:6) contents. Grouper larvae fed lipid supplemented diets, tissue C20:5 and C22:6 increased when dietary lipid level increased. These results suggest that grouper larvae are capable of synthesizing HUFA from dietary lipid and they may have limited or no ability to synthesize HUFA when they fed the dietary without lipid supplementation. Compare with weight gain and survivals were increased with increasing dietary lipid and n-3 HUFA content. The final weight and weight gain of larvae fed the diet without lipid were significantly lower than those of larvae fed other diets, but there were no differences between the 5% to 20% groups. Survival significantly increased with increasing dietary lipid levels from 5% to 15% (P <0.05), and then decreased .The survival of larvae fed the diet without lipid was significantly lower than that of larvae fed other diets. Experiment 2：This study was conducted with grouper larvae of E. coioides and E. lanceolatus to investigate the effects of different dietary lipid source on growth, survival, tissue fatty acid composition. Six treatment diets were prepared using purified ingredients incorporating fish oil, linseed oil, sesame oil, soybean oil, olive oil and beef tallow. The best growth was recorded for E. coioides larvae given the diet having fish oil(weight gain was 231.81%), followed by the beef tallow diet (35.51%), the linseed oil, soybean oil and olive oil diets (22.03%-19.63%) and the sesame oil diet (12.66%). The survival was 75% to 84%. The fatty acid profile of the muscle was shown to be influenced by dietary fatty acid composition. E. lanceolatus, the best growth was recorded for larvae given the diet having fish oil (weight gain was 2105.09%), followed by the beef tallow diet (538.71%), the olive oil diet (488.20%), soybean oil diets (353.00%), the sesame oil diet (334.37%) and the linseed oil diet (332.72%). The survivals were 73% to 95%. The fatty acid profile of the muscle was shown to be influenced by dietary fatty acid composition. The results of this laboratory study indicated that a combination of fatty acids is important for growth and survival of this two species. Experiment 3：A feeding experiment was conducted to study the effects of dietary L-carnitine and lipid levels on the growth, muscle and liver fatty acid profile of E. lanceolatus larvae (initial mean weight 0.136 g). Two levels of supplemental lipid, 5 or 14% were tested in combination with three levels (0, 0.5 and 1%) of L-carnitine. Each diet was randomly assigned to three replicate groups of groupers larvae for 42 days. The fatty acid compositions of grouper larval muscle and liver were influenced by dietary L-carnitine and lipid. The n-3 high unsaturated fatty acids (n-3 HUFA) of muscle and liver of grouper larvae fed diets supplemented with L-carnitine were significantly lower than that of grouper larvae fed diets without L-carnitine. The grouper larvae fed diets containing 14% lipid had the significantly higher weight gain than those fed diets containing 5% lipid. The grouper larvae fed diets containing 5% lipid and without L-carnitine supplementation had the worst weight gain. The grouper larvae fed diets containing 14% lipid and supplemented with 0.5% L-carnitine had the highest weight gain among treatments. The hepatosomatic index (HSI) of grouper larvae increased with dietary lipid increasing, while HSI of grouper larvae decreased with the increasing dietary L-carnitine. Lipid contents of muscle and liver of grouper larvae increased with increasing dietary lipid level, whereas lipid levels of muscle and liver of grouper larvae fed diets supplemented with L-carnitine decreased. The muscle protein content significantly increased with increasing dietary L-carnitine. The survival of grouper larvae fed diet containing 14% lipid was significantly higher than that of grouper larvae fed diets containing 5% lipid. This study revealed the positive effects of dietary L-carnitine supplementation on growth of grouper larvae. Experiment 4：A study was undertaken to examine the effect of different dietary L-carnitine (0 and 0.5%) and lipid (5 and 14%) supplementation on growth and fatty acid profiles of fish fed either with 0% L-lysine or 2.83% L-lysine. Initial body weight 0.08g grouper larvae (E. lanceolatus) were stocked (24 aquaria, 10 fish aquarium-1) and fed for 42 days. Dietary L-carnitine had a clear effect on growth performance, but dietary lysine supplements had no effect. Clear effects on muscle and liver fatty acid profiles were observed in 0.5% L-carnitine fed fish compared with 0% L-carnitine fed fish. The primary muscle fatty acids affected were docosapentaenoic acid (DPA, 22:5 n-3) and docosahexenoic acid (DHA, 22:6 n-3). The liver fatty acid balance suggested that 22:6 n-3 disappeared (apparently by β-oxidation) more readily than 22:5 n-3. Dietary L-carnitine improve growth, these data support the hypothesis that L-carnitine can enhance the metabolism of long-chain fatty acids to wardsβ-oxidation.